[05/23/03] The forecast crest on the Mississippi River at Vicksburg has been lowered by half a foot, and the change could be good news for those whose land is flooded or threatened.

The Lower Mississippi River Forecast Center in Slidell, La., had predicted a crest of 42.5 feet on Sunday, but Thursday evening lowered the crest to 42.0 feet, also on Sunday. Flood stage at Vicksburg is 43.0 feet.

The former prediction had been based on the crest at Cairo, Ill., where the Upper Mississippi and Ohio rivers join to form the Lower Mississippi, and some assumptions on what the Arkansas River would do, said David Welch, a forecaster with the forecast center.

“We’ve been able to get a better handle on the Arkansas,” Welch said, adding that the more accurate information on actual flows allowed the forecast crest at Vicksburg to be lowered.

The Mississippi was at 41.4 feet this morning, up 0.5 from Thursday morning’s reading.

If the lowered crest happens, “it would be a blessing for people north of town,” said Wayland Hill of the Water Control Branch of the Vicksburg District Corps of Engineers.

But, Hill said, the lowered crest won’t have much effect on the area of Mississippi behind the Mainline Mississippi River and Yazoo River levees and above the Steele Bayou and Sunflower River control structures.

“We might be able to open the gates a day earlier,” he said.

The gates on the control structures were closed to prevent the Mississippi and Yazoo rivers from backing up and flooding the lower Delta. As a result, rain water that falls in the Delta cannot drain.

With water already on the ground, the water behind the control structures is expected to crest between 88.0 feet and 88.5 feet mean sea level about June 1. With normal rainfall, the crest could be as high as 89.5 feet by about June 10.

At those levels, about 266,000 acres of land in the Delta would be under water with about a third of that, or about 91,000 acres, cleared for farming.

This morning the water on the land side of the Steele Bayou structure was 86.7 feet msl, up 0.2 foot; and on the river side, it was 89.2 feet msl, up 0.6 feet.